U.S. patent number 5,297,836 [Application Number 07/906,799] was granted by the patent office on 1994-03-29 for motor car chasis structure.
This patent grant is currently assigned to Jaguar Cars Limited. Invention is credited to Daniel Parry-Williams.
United States Patent |
5,297,836 |
Parry-Williams |
March 29, 1994 |
Motor car chasis structure
Abstract
A motor car structure is built up from flat panels joined
together, each panel comprising two mutually parallel spaced apart
structural skins braced with respect to each other by a core of
expanded material united to both skins. Each joint between two
panels comprises a series of integral projections formed on a first
panel by cutting the panel to a required shape and recesses in the
second panel corresponding to the projections. The projections are
inserted and bonded into the recesses by means of an adhesive.
Inventors: |
Parry-Williams; Daniel
(Banbury, GB) |
Assignee: |
Jaguar Cars Limited
(GB)
|
Family
ID: |
10697797 |
Appl.
No.: |
07/906,799 |
Filed: |
June 30, 1992 |
Foreign Application Priority Data
Current U.S.
Class: |
296/203.01;
403/231; 403/381; 296/191; 52/284; 52/275; 403/267; 296/900;
296/187.02 |
Current CPC
Class: |
B62D
27/026 (20130101); Y10S 296/90 (20130101); Y10T
403/4602 (20150115); F16B 2200/30 (20180801); Y10T
403/472 (20150115) |
Current International
Class: |
B62D
27/02 (20060101); B62D 27/00 (20060101); B62D
025/08 () |
Field of
Search: |
;296/187,191,203,29,30,900,901 ;52/275,284,593,594
;403/231,253,263,267,381 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2054915 |
|
May 1971 |
|
FR |
|
361203 |
|
Mar 1962 |
|
CH |
|
2180202 |
|
Mar 1987 |
|
GB |
|
2220724 |
|
Jan 1990 |
|
GB |
|
Primary Examiner: Mitchell; David M.
Assistant Examiner: Pike; Andrew C.
Attorney, Agent or Firm: Davis, Bujold & Streck
Claims
I claim:
1. A motor car structure comprising first and second flat panels
joined together; each panel comprising first and second mutually
parallel spaced apart structural skins, and a core of expanded
material united to both the first and second skins and bracing the
first skin with respect to the second skin of each panel; a joint
between the first and second panels forming part of the structure
comprising a plurality of integral projections formed on the first
panel by cutting the first panel to a required shape, a
corresponding plurality of recesses in the second panel
corresponding to the projections, the projections being inserted
into the recesses, and adhesive bonding the projections into the
recesses; wherein roots defined between said projections are bonded
to one skin of the second panel between the recesses.
2. A structure according to claim 1 wherein the projections are
formed by cutting the first panel across its whole width, thereby
incorporating parts of said first and second skins and of the core
of the first panel in each projection and wherein the recesses
extend through the first skin and into the core of the second panel
but not through the second skin thereof.
3. A structure according to claim 2 wherein the recesses extend the
whole depth of the core of the second panel and the projections are
bonded to the second skin of the second panel while the roots
defined between said projections are bonded to the first kin of the
second panel.
4. A structure according to claim 3 wherein the adhesive is applied
to the whole lengths of the projections and the whole lengths of
the roots between the projections such that the projections become
bonded to the second skin of the second panel in the base of the
corresponding recesses and the roots between the projections become
bonded to remaining parts of the first skin of the second panel
between the recesses.
5. A structure according to claim 1 wherein the recess are formed
at an edge of the second panel.
6. A structure according to claim 5 wherein the projections extend
across the whole depth of the first panel and the roots between the
projections are formed by cutting away only the first skin of the
first panel and the whole of the core of the first panel to level
the second skin of the first panel extending between the
projections and wherein the recesses extend through the first skin
and the whole of the depth of the core of the second panel but not
through the second skin of the second panel.
7. A structure according to claim 1 wherein the first panel is
thinner than the second panel, the recesses in the second panel
extend through the first skin of the second panel and only partly
through the core of the second panel and wherein the projections
are bonded to the core of the second panel and the roots between
the projections are bonded to remaining parts of the first skin of
the second panel between the recesses.
8. A structure according to claim 1 wherein each skin is formed
from metal sheet.
9. A structure according to claim 1 wherein each skin is a
resin-fibre composite.
10. A structure according to claim 1 wherein the core is of
expanded resinous material or expanded resin-fibre composite.
Description
BACKGROUND TO THE INVENTION
The invention relates to motor car structures.
Racing cars and other high performance light-weight motor cars
which may be sports-racing cars or road going sports cars
incorporate a basic vehicle structural element or chassis which is
normally referred to as a tub. The tub normally incorporates a
floor, sides, front and rear bulkheads and possibly extensions of
some of these elements to carry engines, suspensions, transmissions
or other essential parts of the vehicle. In some cases, the tub may
also incorporate a roof in which case the sides have to be
relatively low to permit driver access.
One established material for manufacture of a tub is aluminium or
other light metal sandwich structure. Sandwich material
incorporates two skins united by a core of expanded material. One
popular sandwich material is known as honeycomb material and has a
core constituted by a hexagonal matrix of a material which may be
the same as or different from that of the skins. The established
procedure for joining together flat sandwich panels to form a tub
is by means of angle section strip material bonded and rivetted to
at least one skin of each of the panels being joined.
Joins of this kind add weight to the structure, can result in weak
points in the structure, are time consuming to assemble and require
accurate positioning of rivet holes in the panels and strips.
A more recent development has been to build tubs with a sandwich
structure by laying one skin of fibre-resin composite material on a
former, applying a sandwich core to the first skin and subsequently
laying a second composite skin over the core. With a suitable
former, the floor, sides, bulkheads and other parts of the tub can
be formed integrally, thus reducing or even avoiding the
requirement for joints between individual panels.
Manufacture of a tub in this way is very labour intensive and the
cost can amount to several times that of a corresponding tub
manufactured from flat sandwich panels joined together.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a motor car
structure which can be built from flat preformed sandwich panels
joined together in an effective manner.
The invention is concerned in particular with a motor car structure
comprising flat panels joined together, each panel comprising two
mutually parallel spaced apart structural skins, braced with
respect to each other by a core of expanded material united to both
skins, the panels being joined together by adhesive. The invention
is characterised in that a joint between two panels comprises a
series of integral projections formed on a first panel by cutting
the panel to a required shape, recesses in the second panel
corresponding to the projections, the projections being inserted
into the recesses and bonded into the recesses by means of an
adhesive.
Preferably the roots between the projections are also bonded to a
skin of the second panel between the recesses.
Preferably the projections are formed by cutting the panel across
its whole width, thereby incorporating two skins and the core in
each projection, the recesses extending through a first skin and
into the core of the second panel but not through the second skin
thereof.
Preferably the recesses extend the whole depth of the core and the
projections contact and are bonded to the second skin while the
roots between the projections are bonded to the first skin.
The adhesive may be applied to the whole lengths of the projections
and the whole lengths of roots between the projections such that
the projections become bonded to the second skin in the base of the
corresponding recesses while the roots between the projections
become bonded to the remaining parts of the first skin between the
recesses.
The recesses may be formed at an edge of the second panel. The
projections may extend across the whole depth of the first panel,
the roots between the projections being formed by cutting away only
one skin and the whole of the core to leave the second skin
extending between the projections, the recesses extending through
one skin and the whole of the depth of the core but not through the
second skin.
With one variant, the first panel has a relatively thin depth
compared with the second panel, recess in the second, relatively
thick, panel extend through a first skin and only partly through
the core, the projections are bonded to the core and the roots
between the projections are bonded to the remaining parts of the
first skin between the recesses.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described by way of
example only with reference to the accompanying drawings in
which:
FIG. 1 is a diagrammatic perspective view of a partly completed tub
constructed in accordance with the present invention;
FIG. 2 is a more detailed perspective representation of a small
number of panels being joined together to form part of a tub;
FIGS. 3A and 3B are each sectional views of two joints about to be
assembled together;
FIGS. 4A and 4B are corresponding views of a joint between deeper
panels;
FIG. 5 is a perspective view of two panels about to be joined
together at their edges;
FIG. 6 is a view of a joint between panels of different
thicknesses; and
FIG. 7 is a partial diagrammatic sectional view showing the skin
and core as a resinous material.
DESCRIPTION OF A PREFERRED EMBODIMENT
FIG. 1 broadly illustrates the nature of a tub and gives a general
indication of joints between panels constructed in accordance with
the invention. The tub incorporates a floor panel 11. Two side
panels 12, only one of which is shown in the interests of clarity,
are arranged one to each side of the vehicle. All of the panels
including panels 11 and 12 are made from aluminium honeycomb
material incorporating two parallel flat aluminium skins spaced
apart by and united to an aluminium alloy hexagonal honeycomb
matrix. The design of the vehicle requires that the side panels 12
are closer together at the front and rear of the vehicle than they
are in the region of the driver's cab and floor panel 11. Bends are
incorporated in the flat panel by cutting part way through the
panel, bending the panel along the partial cut line and then
reinforcing the bend, particularly the skin which has had to be cut
through to provide the bend. In this way, the side panel in effect
becomes a series of smaller flat panels between the bends.
The driver's cockpit area in the car lies between a rear bulkhead
assembly 13 and a front bulkhead assembly 14. The rear bulkhead
assembly comprises a vertical bulkhead 15, an inclined bulkhead 16
referred to as a seat bulkhead because it supports the seat back of
the car, a horizontal panel 17 joining the top of panel 16 to a
central region of panel 15 and a longitudinal vertical panel 18
referred to as a battery bulkhead. In the completed vehicle its
battery is positioned in the space defined by a side panel (not
shown) and panels 11, 15, 16, 17 and 18. The front bulkhead
assembly 14 is similarly made up from a series of panels arranged
in a configuration that provides suitable structural strength,
space for the driver's legs and mounting points for functional
parts of the vehicle such as the steering column, steering rack and
front suspension. This structure is not described in detail because
the exact configuration of the tub as a whole is incidental to the
invention.
In some cars of tub construction, the tub ends at the vertical
bulkhead 15 of the rear bulkhead assembly 13 and a stressed
engine/transmission unit is secured directly to the bulkhead. The
rear suspension and other functional parts of the vehicle are then
mounted on the engine/transmission assembly. In the example
described here, the side panels 12 extend rearward from the
vertical bulkhead 15 of the rear bulkhead assembly 13 and are
joined together by a further horizontal panel 19.
The invention is concerned particularly with the nature of joints
between panels in a motor car tub structure as shown in FIG. 1.
Details of such joints will now be explained.
FIG. 2 shows the rear bulkhead assembly 13 on a larger scale. The
joint between panels 15 and 18 is typical. Panel 18 incorporates
two projections 21 on each of its front, rear and lower edges and a
single projection on its upper edge. Projections 21 are shown
engaged in corresponding recesses 22 in the rear bulkhead 15. In a
similar way, a horizontal row of recesses 23 is provided across the
central region of bulkhead 15 to receive projections 24 at the rear
edge of panel 17. Panels 15, 16 and 17 also have projections such
as 25 at their outer ends for engagement in corresponding recesses
in a side panel 12.
FIGS. 3A and 3B show still further details of typical joints. These
Figures are illustrative of joints as such and do not correspond to
particular panels in the tub shown in FIGS. 1 and 2. A first panel
31 is joined to a second panel 32 to form a joint 33. The first
panel 31 has aluminium alloy skins 26 and 27 and an aluminium alloy
honeycomb core 28 and the second panel has skins 37 and 42 and a
core 38. By way of illustration, a cross sectional view through a
different part of an identical joint 33A is shown between panels
31A and 32. Joint 33 shows a cross sectional view at a projection
34 whereas joint 33A shows the situation in a region between two
projections. FIG. 3A shows the two joints prior to assembly and
FIG. 3B shows the corresponding joints after assembly. The joint 33
incorporates a projection 34 in the form of a rectangular block
corresponding to a projection 21 from FIG. 2 about to be inserted
within a recess 35. Similarly, at joint 33A, the root 36
represented by the region between two adjacent projections 34 or
the space beyond the last projection is about to come into contact
with an upper skin 37 of panel 32. FIG. 3 shows that recess 35 is
substantially the whole depth of the core 38 as well as extending
through skin 37. When core 38 is of honeycomb material it is in
order to leave a small depth of the core at the base of the recess
35 as will be explained.
Prior to final assembly, beads 39 and 41 of adhesive are laid on
the panel 32 along the whole of the line of the joint. These may be
separate beads applied within the recesses and between the recesses
or may be a continuous bead which runs up and down over the edge of
the recess. On final assembly as the panels are pushed from the
position shown in FIG. 3A to the position shown in FIG. 3B, the
adhesive spreads and takes up a position to give effective bonding
between the panels. The quantity of adhesive in the bead should be
sufficient to ensure that it spreads beyond the edges of panels 31
and 31A to ensure that the skins of these panels are embedded in
the adhesive. One factor determining the requirement for the
adhesive is the nature of the surface of the core at an exposed
edge of the bead. Also, if a small amount of core has been left at
the base of the recess, there should be sufficient adhesive to
permeate the remaining core and bond effectively with the adjacent
lower skin 42. Similarly, at joint 33A, there must be sufficient
adhesive to spread and embed both skins.
FIGS. 4A and 4B show part of a joint 43 corresponding generally to
joint 33A but for a greater depth of sandwich material. The
arrangement of FIGS. 3A and 3B is suitable for panel depths of the
order of 15 mm. However, for panels with a depth of the order of 50
mm, the quantity of adhesive required in the arrangement of. FIGS.
3A and 3B would be excessive. For this in FIGS. 4A and 4B; two
separate beads are shown, one adjacent each skin of the panel. FIG.
4A shows the situation when the panels are about to be joined
together and FIG. 4B shows the arrangement after joining. A similar
technique to that shown in FIGS. 4A and 4B may also be employed
within a recess.
Where the first panel with its projections is of a relatively thin
depth compared with the depth of the second panel with the
projections, it is unnecessary for the recesses to extend the whole
depth of the second panel. In such a case, the roots between
projections are joined to an upper skin as previously described
while the projections are bonded into the recesses by bonding the
projections to the core of the second panel.
Where panels are to be joined at inclined angles instead of at a
right angle, the recesses should be correspondingly inclined. If
the basic recess cutting equipment is only capable of operating
perpendicular to the surface of a panel, the recess should be cut
undersize initially and then cut or pushed back manually to the
desired size at the required angle.
When joining two panels edge to edge at a right angle to each
other, for example as shown for panels 12 and 19 in FIG. 1, the
arrangement of projections and recesses may be as described with
reference to FIGS. 2, 3A and 3B but with the recesses formed at an
edge of the panel.
However, this leaves some core exposed and does not achieve a
double skin to skin bonding between the panels in the region
between the recesses.
A preferred alternative is illustrated in FIG. 5. Panel 51 is shown
as having two recesses 52 and 53 in its edge 54. Panel 55 has two
corresponding projections 56 and 57 for engagement in recesses 52
and 53. Instead of cutting the profile of the panel 55 through its
whole depth to form the projections 56 and 57, the panel has been
cut through only one skin and the whole of the core, leaving part
of the other skin as a web 58 extending between the projections 56
and 57 and extending beyond these projections.
When the two panels are brought together, the projections fit into
the recesses and the web 58 closes off what would otherwise be
exposed core in panel 51. The outer skins of both panels thus come
into juxtaposition and can be bonded one to the other. This
arrangement described with reference to FIG. 5 can be adapted to
panels of different thicknesses.
Once a tub as illustrated in FIG. 1 or parts of a tub as
illustrated in FIG. 2 have been assembled by means of joints such
as described in FIGS. 3A, 3B, 4A, 4B and 5, the assembly should be
subjected to an environment in which the adhesive cures
effectively. This may require no more than maintaining an ambient
temperature of the order of 20.degree. C. or could involve placing
the assembly in a higher temperature environment, depending on the
properties of the adhesive chosen.
Instead of aluminium, other light metals such as titanium could be
used. As a further alternative, the panels could be constructed
from skins of resin-fibre composite and a core of expanded resin
material or of expanded resin-fibre composite. The metal and resin
or composite materials could be mixed, using either material for
the skins and the other material for the core.
* * * * *